The present invention relates to a brush seal system for sealing a clearance between components of a turbo engine that are movable in relation to one another, in particular a thermal gas turbine, including a brush seal housing, which accommodates at least one brush head of a brush seal, where the brush seal housing includes a first sheet metal part having a cover plate section and a second sheet metal part having a support plate section. The invention also relates to a thermal gas turbine having a brush seal system.
Various brush seal systems for turbo engines, in particular thermal gas turbines, are known from the prior art. There are numerous application cases in which two parts that are movable in relation to one another are to be sealed non-hermetically with respect to one another. Such an application case includes, for example, sealing an annular clearance through which gas flows between a stator and a rotor in a gas turbine, for example, for an airplane. Brush seal systems are often used for non-hermetic sealing of annular interspaces between assemblies rotating in relation to one another, because brush seal systems are lighter and more compact than labyrinth seals while providing the same sealing effect. For example, U.S. 2002/0020968 A1 discloses various brush seal systems for aircraft engines. The brush seal systems each includes a multipart brush seal housing, which accommodates the actual brush seal and secures it in position. Each brush seal housing therefore consists of at least one support plate and one cover plate, which are joined together and extend together around at least one brush head of the brush seal system in a U shape, securing it to prevent it from falling out of the brush seal housing. The cover plate and/or the upstream region in the direction of flow of the two-part brush seal housing should primarily hold back problematical flow effects on a brush bundle protruding away from the brush head and out of the brush seal housing, while the support plate of the brush seal housing which is situated downstream as seen in the direction of flow serves as a support element which should prevent the brush bundle from sagging in the axial direction of the turbine engine, in particular the aircraft engine, based on the pressure difference over the brush seal housing. One-piece brush seal housings, which are also designed to have at least an approximately U-shaped cross section, are also known.
However, one disadvantage of the known brush seal systems can be regarded as the fact that they usually have brush seal housings that are designed to be separate and require a comparatively large installation space which is not available in all turbo engines and in particular not in all engine applications.
The object of the present invention is therefore to provide a brush seal system of the type defined in the introduction, which is designed so that it requires a comparatively small installation space for installation in a turbo engine. Another object of the invention is to provide a thermal gas turbine which such a brush seal system.
A first aspect of the invention relates to a brush seal system for sealing a clearance between components of a turbo engine that are movable in relation to one another, in particular a thermal gas turbine. In particular a clearance between a rotor and a stator of a thermal gas turbine such as an aircraft engine is to be sealed. The brush seal system according to the invention therefore includes a brush seal housing which accommodates at least one brush head of a brush seal where the brush seal housing includes a first sheet metal part having a cover plate section and a second sheet metal part having a support plate section. The first sheet metal part has an axial flange for forming a fish mouth seal on an end opposite the cover plate section. Due to the integration of the brush seal housing and the fish mouth seal into one component, it has a double function, which leads to a significant reduction in the required installation space in comparison with a brush seal housing and fish mouth seals that are designed separately. The axial flange functions as a deflector of the fish mouth seal, for example. A radially inner platform of a guide vane arrangement with one or more guide vanes on which the brush seal system is mounted is situated on the outside radially of the axial flange and opposite it. An axial flange of an upstream and neighboring rotor blade arrangement having one or more rotor blades may be arranged radially between the inner platform of the guide vane arrangement and the axial flange. A lightweight design is also possible and can be implemented inexpensively due to the sheet metal design. The brush seal system according to the invention is suitable in particular for integration of a brush seal into an intermediate step seal of a turbo engine, in particular a thermal gas turbine, from the standpoint of lightweight design.
In another advantageous embodiment of the brush seal system according to the invention, the second sheet metal part includes a mounting section for direct or indirect mounting of the brush seal system on a guide vane, a guide vane cluster or a guide vane ring of the turbo engine on an end opposite the support plate section. In addition to the design of a brush seal and a partial element of the fish mouth seal, due to this design of the brush seal system according to the invention, this can also assume a fastening function via the mounting section of the second sheet metal part. This integrated design of the brush seal system according to the invention can advantageously replace the use of separately designed brush seal housings, fish mouth seals and mounting devices for the brush seal system on a guide vane, a guide vane cluster or a guide vane ring. In particular this leads to advantages due to the small number of components that require only a few joining operations. Therefore, novel, faster and more efficient manufacturing methods are also possible and can be ready for mass production relatively quickly. It is also possible to replace individual components separately, which greatly increases the reparability of the system as a whole. In addition, the tightness and robustness of the brush seal system according to the invention are ensured. Due to the use of conventional materials, namely sheet metal, this yields an excellent geometric scalability of the brush seal system according to the invention to be manufactured.
Since the brush seal housing is designed in multiple parts, in particular in two parts, the structural design freedom of the brush seal system according to the invention can be further increased.
In another advantageous embodiment of the brush seal system according to the invention, it includes at least one reinforcing element, which is secured on the second sheet metal part in the region of the supporting sheet metal section. The mechanical properties of the brush seal system can therefore be improved significantly.
In additional advantageous embodiments of the brush seal system according to the invention, the supporting sheet metal section of the second sheet metal part has a support element for contact with a brush bundle of the brush seal. This reliably prevents sagging of the brush bundle in the axial direction of the turbo engine, in particular the aircraft. It is possible here for the support element to be designed in one piece with the supporting sheet metal section or as a separate element. An advantageous increase in the design freedom of the brush seal system is achieved in that the support element is designed as a separate component from the second sheet metal part because there is a corresponding separation of the functions “brush seal carrier,” which is also satisfied by the brush seal housing and/or the second sheet metal part, and “support of the brush bundle,” which is now taken over by separate support elements in this embodiment of the invention. Due to the separation of the function regions of the brush seal system, in addition to an increased geometric design freedom, there is also simplified manufacturing as well as an increased simplification and ease of repairs, because in a damage incident, i.e., after scraping against a rotor, for example, only the separate support element must be overhauled or replaced, but the brush seal housing carrying the brush seal need not. Accordingly, much greater freedom is allowed in the design of the brush seal housing with regard to its mechanical and structural behavior. Another advantage is that the brush seal system according to the invention can be adapted particularly easily to different intended applications and types of engines because the same brush seal housing need only be combined with different brush seals and support elements in order to adapt the brush seal system to radial clearances of different sizes, for example. The advantages mentioned last are also derived for the case of a one-time and/or integral design of the support element with the second sheet metal part. Furthermore, there is the possibility here that an end region of the separately designed support element might be arranged closer to an end of the brush bundle opposite the brush head than an end region of the second sheet metal part. This ensures that in the case of any scraping contact, only the support element which is closer to the ends of the brush bundle is damaged, but not the second sheet metal part which is at a greater distance from the ends of the brush bundle. This permits designs of the brush seal system that are much more tolerant of scraping because, in the event of damage, it is not necessary to dismantle the brush seal housing and/or the brush seal. In a further embodiment of the invention, an additional increase in the design freedom is given by the fact that the support element, which is designed separately, is designed in a ring shape and/or in the shape of ring segments. In particular a ring segment-shaped design of the support element facilitates any repairs in particular because as a rule it is only necessary to repair or replace a damaged ring segment but not the entire ring. Basically, the brush seal housing and/or the entire brush seal system can be designed to be segmented. In another advantageous embodiment of the invention, it is provided that the separately designed support element is made of a different material than the second sheet metal part and/or has a different wall thickness than the second sheet metal parts. Based on the free choice of materials and/or the different wall thicknesses, the brush seal system can be designed with a particularly great variability and optimally adapted to different intended applications.
Additional advantages are achieved when the separately designed support element is arranged between the supporting sheet metal section and the reinforcing element. In this way, the support element can be secured in position by a type of clamping. In addition, the support element and the reinforcing element may advantageously be secured on the supporting sheet metal section of the second sheet metal part or on other regions of the second sheet metal part with the help of a common fastening means. This permits a particularly rapid, easy and inexpensive assembly and disassembly of the support element.
In another advantageous embodiment of the invention it is provided that the reinforcing element is designed as a curved sheet metal plate and/or the reinforcing element is riveted to the second sheet metal part of the brush seal housing and/or at least one sliding element, in particular a sliding block, is arranged between the reinforcing element and the second sheet metal part of the brush seal housing. Since the reinforcing element is designed as a curved sheet metal plate, a resilient flexible reinforcement of the brush seal housing can be achieved expensively and with a simple design. If the reinforcing element is riveted to the second sheet metal part of the brush seal housing, a form-fitting and/or force locking connection between the reinforcing element and the brush seal housing on the whole is achieved inexpensively and with a simple design. Due to the arrangement of a sliding block between the reinforcing element and the second sheet metal part of the brush seal housing, a bearing site with one degree of translatory freedom for spoke centering of the brush seal system is ensured with a simple design. The bearing site is formed by the sliding element, in particular a sliding block such that the sliding block in the installed state of the brush seal system engages in a corresponding groove of a guide vane, for example, or a guide vane cluster. Due to the spoke centering, changes in dimension between the components arranged coaxially and to be sealed with respect to one another, i.e., between a stator and a rotor, that are due to thermal influences can be compensated better. The sliding element(s), in particular the sliding blocks, may be designed as separate modules and may be connected to the reinforcing element by riveting, for example.
In other advantageous embodiments of the brush seal system according to the invention, the first and second sheet metal parts may be designed in one piece or as separate components. A design as separate components may lead to a simplified replacement or repair of the individual parts, or of the brush seal system on the whole. The first and second sheet metal parts may be joined together in a form-fitting and/or physically bonded manner. A one-piece design of the first and second sheet metal parts reduces the number of parts to be installed so that a time advantage is achieved in the manufacture and installation of the brush seal system.
In another advantageous embodiment of the brush seal system according to the invention, the reinforcing element on one end opposite the contact element, includes an axial flange to form an additional fish mouth seal situated downstream from the first fish mouth seal formed with the first sheet metal part, based on the position. Again in this case, the axial flange functions as a deflector for the fish mouth seal, for example. The radially inner platform of the guide vane arrangement with one or more guide vanes on which the brush seal system is mounted via the mounting section of the second sheet metal part on the outside of and opposite the axial flange radially. An axial flange of a rotor blade arrangement having one or more rotor blades may be arranged radially between the inner platform of the guide vane arrangement and the axial flange downstream and nearby. Due to the integration of a second axial flange to form an additional fish mouth seal situated downstream, this advantageously yields a compact and integral design of the brush seal system with integrated fish mouth seals which in turn requires a smaller installation space in comparison with known designs.
A second aspect of the invention relates to a thermal gas turbine, in particular an aircraft engine having at least one brush seal system which is designed according to the first aspect of the invention. The resulting features and advantages thereof can be derived from the descriptions of the first aspect of the invention wherein advantageous embodiments of the first aspect of the invention are to be regarded as advantageous embodiments of the second aspect of the invention and vice versa.
In an advantageous embodiment of the thermal gas turbine according to the invention, it is provided that the brush seal housing of the brush seal system for sealing the clearance between a rotor and a stator of the gas turbine is secured on the stator. In other words, it is provided that the brush seal housing is directly or indirectly secured on a stator of the gas turbine, so that the ends of the brush bundle opposite the brush head are in contact with the respective surface of the rotor. This creates an arrangement of the brush seal system that has a particularly stable mechanical design and is more reliable in operation.
In another embodiment, it has been found to be advantageous if the stator is designed as a guide vane and/or as a guide vane cluster and/or as a guide vane ring. If the stator has a segmented design, it has been found to be advantageous if the brush seal system has a segmented design because a particularly simple assembly and disassembly are made possible in this way.
Additional features of the invention are derived from the claims, the exemplary embodiments and on the basis of the drawings. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned in the exemplary embodiments which follow may be used not only in the particular combination given but also in other combinations without going beyond the scope of the present invention.